1. Field of the Invention
The present invention relates to a display for image forming apparatus of copying machines, laser beam printers and others which is so contrived that the number of processing sheets such as copy and disabled paper feeding by the paper feed system can be indicated commonly on one display.
2. Description of the Prior Art
The image forming apparatus of conventional copying machines and laser beam printers are provided with a paper sensing switch to check whether or not the paper to be supplied is set in the cassette or on the manual paper supplying mechanism as an example of the means to find if paper feeding on the paper feeding pass is possible or not.
Such apparatus are so composed that a display for dedicated use which is provided in the operation unit indicates no paper when the paper sensing switch detects no paper passing. While the number of processing sheets such as copy is set by the operator prior to the copying operation.
The indication of the above mentioned number of processing sheet is also given on an independent display for dedicated use, and the number of processing sheets is indicated separately from the indication of disabled paper feeding due to no passing paper.
As described above, however, it is uneconomical to provide a display to indicate disabled paper feeding separately from the display to indicate the number of processing sheets like preset number of sheets to be copied or the number of remaining sheets left to be copied further.
Accordingly, the display of the copying machine stated in the Official Gazette of U.S. Pat. No. 4,470,692 for example, is so composed to indicate both the preset number of sheets to be copied (number of processing sheets) and other indications (such as no paper to be copied) commonly on one display.
The display of the copying machine shown in the Official Gazette of U.S. Pat. No. 4,470,692 is advantageous in that the number of display units can be decreased. However, the display has a problem in that the number of sheets to be copied (the number of processing sheets) can not be confirmed until the processing like setting copy paper into the cassette is completed because the display is so composed that display concerning the number of sheet to be copied is not given while indication of no paper, for example, is given.
Accordingly, the trouble is that the rule-of-thumb guide for the number of sheets to be supplied is unknown to the operator in such a case when he realizes that the machine has been stopped and tries to supply paper. In addition, the display of the copying machine shown in the Official Gazette of U.S. Pat. No. 4,470,692 is disadvantageous in that the cost becomes higher by the number of the required switch for sensing copy paper although it is advantageous in that the number of units of display can be decreased as mentioned above.